As indicated, I top off by adding back to the developer about 50ml of fresh solution for every 100 square inches of print development. I use dichromate control and add back the dichromate in the fresh solution in the same ratio as it is found in the main solution. For example, if the main solution contains 2ml of a 5% potassium dichromate solution per liter of solution, when I top it off with 100 ml of fresh solution I also add four drops potassum dichromate (where twenty drops = 1 ml).

Sandy

Originally Posted by photomc

would like to add one more question to Neils excellent post....what is meant by "topping off" ? Do you add x amount of water, water + PO? Sorry, this is probably clear to everyone but me...I understand if you made up 1 liter of PO, after a period of use, it could be reduced down to say 950 ml, would you then add water back to equal 1 liter, or would you add 50 ml of water + x grams of PO?